The present disclosure is related to packaging and transport of electronic equipment used in the oil and gas industry and, more particularly, to downhole electronic assemblies that can be secured to various downhole tools for downhole use.
In the exploration and production of hydrocarbons, various downhole tools are frequently lowered into a borehole, such as drilling assemblies, measurement tools, and production devices. Such downhole tools often include electronic equipment and modules used for various purposes, such as controlling the downhole tools, communicating with a surface location, and storage and analysis of monitored wellbore data. Such electronic modules typically include circuit boards, such as printed circuit boards (PCBs) that are packaged to provide protection from harsh downhole environmental conditions, such as elevated temperatures and pressures, vibration, thermo-mechanical stresses, and thermal shock. Prior to being installed in a downhole tool for use, electronic modules must also be capable of surviving transport and field handling without premature failures resulting from shock and vibration.
Conventional approaches to packaging downhole electronic modules include “potting” the electronic modules in a foam or silicone substance. While potting is a viable solution for surviving harsh downhole environments, it is subject to potential manufacturing and field maintenance problems. For example, after a significant investment in building and testing the electronic modules, they can become damaged beyond repair during the subsequent foaming/potting process. When the potting cures, for instance, it can move wires and/or place stress on various electronic components of the circuit board, thereby increasing the failure rate of the circuit board.
Another conventional approach to packaging a downhole electronic module for downhole use includes wet-mounting the electronic module in a particular downhole tool. Again, this approach may provide a viable downhole solution for withstanding harsh downhole environments, but permanent damage often results from the aggressive procedures required to remove the electronic modules for maintenance or replacement.
In drilling assemblies, packaging downhole electronic modules often includes clamping the circuit boards into a simple edge rail structure. In this configuration, each circuit board acts as a primary support structure, which does not offer adequate strength, stiffness, or mechanical dampening losses to properly retain the electronic components that are mounted to the circuit board. Attempts to retain the circuit boards by bonding them to the underlying downhole tool of the drilling assembly provide some improvement, but complicate removal and reinstallation of the downhole electronic module.